Telecine reference element, system, and method for providing scene exposure information

ABSTRACT

A method of transferring a scene recorded on photographic negative film to video using a telecine is disclosed comprising the steps of: 
     a) setting up the telecine so that predetermined waveform readings are obtained for a reference element comprising at least one gray scale portion comprising density patches corresponding to three known density values; 
     b) storing the telecine set-up settings; 
     c) loading a scene on photographic negative film into the telecine wherein the scene includes a gray card; 
     d) using the stored telecine settings to effect transfer of the scene to video; 
     e) determining red, green and blue video voltages for the gray card; and 
     f) converting the red, green and blue video voltages to Transfer Points between 0 and 50 to provide exposure information for the scene. 
     The reference element preferably comprises density patches which correspond to densities obtained in a color negative film after correctly exposing the film to a target comprising a 3% reflectance black, an 18% reflectance gray and a 90% reflectance white region, and standard photographic processing. Advantageously, the gray scale portion fills a full frame on the element. In a preferred embodiment of the reference element, the gray scale portion is horizontally arranged thereon. The red, green and blue video voltages are converted to Transfer Points between 0 and 50 to provide exposure information analogously to Printer Light values obtained for dailies or test print films.

FIELD OF THE INVENTION

The present invention relates to improvements relating to the use oftelecines, and is more particularly concerned with the control of thetelecine transfer of motion picture film to video.

BACKGROUND OF THE INVENTION

It is well known that film dailies or rushes are conventionally producedas a motion picture is shot. These dailies or rushes are processed andthen viewed by the director, the producer, the film editor, etc. workingon the production to determine whether the scenes shot are acceptable.Each person on the production team assesses the dailies for differentelements relevant to their respective roles in the team.

"Printer Light" information is also provided which assists thecinematographer/director of photography to determine whether the sceneswere shot with a satisfactory exposure. This Printer Light informationis determined from the settings of a conventional motion picture filmprinter required to produce a print with laboratory aim densities. Thisinformation is obtained by passing white light from a scene throughdichroic filters to split the light into its three components, red,green and blue. The three light components are then used to expose atest film strip from which the densities corresponding to theintensities of the red, green and blue components of the light can bemeasured and compared with standard densities which correspond to an"ideal" exposure. The densities produced by the red, green and bluelight components on the test film strip give an indication of theexposure given to the original film as the scene was recorded. PrinterLight information provides values between 0 and 50, the neutral valuesbeing 25, 25, 25 and correspond to the ideal exposure. Printer Lightvalues greater than or less than the neutral values correspond to over-or under-exposed scenes respectively, with each Printer Light unitcorresponding to 0.025 units in Log Exposure.

However, there is an increasing demand for motion picture negative filmto be transferred to video, and the film is never printed as such, asmost film programs made specifically for television, for example,episodic shows, movies of the week and commercials, are transferred tovideo tape prior to showing. Telecine machines enable this transfer tobe achieved. Furthermore, in feature film production, video dailies arereplacing the film dailies or rushes and non-linear editing techniquesare replacing conventional film editing.

When transferring negative film to video tape, the colorist, operator ofa telecine, needs to adjust the settings of the telecine, in particular,gamma (or contrast), lift (or detail in the black areas of the scene)and gain (or brightness), so that the transfer of the film is optimized.This may be time-consuming if the film has not been correctly exposed,the color balance is incorrect etc., and adjustments have to be made.Several film test targets have been developed which are designed toassist the set up and maintenance of telecine equipment, and therebyoffer operators nominal starting points for a film to video transfersession. Such targets, such as Eastman Kodak Company's Telecine AnalysisFilm (TAF), typically include a color bar test pattern and a neutralgray scale.

PROBLEM TO BE SOLVED BY THE INVENTION

With video dailies replacing film dailies, directors of photography fora production need to be provided with information relating to the cameraexposure directly from the telecine transfers in a similar way PrinterLight information was previously obtained from film dailies. While sceneexposures may be estimated from telecine transfers made on telecines setup with prior art film test targets, there is no previously availablesystem which provides scene exposure information directly from atelecine transfer of a film negative in an accurate manner analogouslyto Printer Light information.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodof transferring a scene from negative film to video, and in particularto provide scene exposure information similar to Printer Lightinformation based upon such transfer.

It is a further object of the present invention to provide a telecinereference element, which can be used with a telecine transfer system, totransfer any negative film to video and provide scene exposureinformation.

In accordance with one aspect of the present invention, there isprovided a method of transferring a scene recorded on photographicnegative film to video using a telecine, the method comprising the stepsof:

a) setting up the telecine so that predetermined waveform readings areobtained for a reference element comprising at least one gray scaleportion comprising density patches corresponding to three known densityvalues;

b) storing the telecine set-up settings;

c) loading a scene on photographic negative film into the telecinewherein the scene includes a gray card;

d) using the stored telecine settings to effect transfer of the scene tovideo;

e) determining red, green and blue video voltages for the gray card; and

f) converting the red, green and blue video voltages to Transfer Pointsbetween 0 and 50 to provide exposure information for the scene.

In preferred embodiments of the invention, the reference elementcomprises density patches which correspond to densities obtained in acolor negative film after correctly exposing the film to a targetcomprising a black, a gray and a white region, and standard photographicprocessing. More preferably, the black region of the target is a 3%reflectance, the gray region is an 18% reflectance and the white regionis a 90% reflectance. Advantageously, the gray scale portion fills afull frame on the element. In a preferred embodiment of the referenceelement, the gray scale portion is horizontally arranged thereon.

The red, green and blue video voltages are converted to Transfer Pointsbetween 0 and 50 to provide exposure information analogously to PrinterLight values obtained for dailies or test print films.

In accordance with another embodiment of the present invention, there isprovided a system for providing exposure information during the transferof a scene, including a gray card, recorded on negative film to videousing a telecine, the system comprising:

a reference element as described above, the element being used forsetting up the telecine so that predetermined waveform readings areobtained for the gray scale portion of the element;

conversion means for determining red, green and blue video voltages forthe gray card and for converting these voltages to Transfer Pointsbetween 0 and 50; and

display means for displaying the Transfer Points for the scene.

Advantageous Effect of the Invention

In accordance with the present invention, a reporting system similar toPrinter Light type information can be provided which facilitatescommunication between colorists and cinematographers/directors ofphotography. Moreover, an aid to correct exposure is provided so that itis possible to predict the outcome of light settings on a release printor on a video transfer. Furthermore, the telecine set-up procedure fortransfer of a negative film to video tape is much simplified providing areliable starting point for the transfer of substantially all negativefilm stocks.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference will nowbe made, by way of example only, to the accompanying drawings in which

FIG. 1 illustrates a reference element in accordance with the presentinvention; and

FIG. 2 shows a green sensitometric curve showing the three points whichare incorporated into the reference element of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

It has been determined that the tone scale of processed color negativefilm may be defined by three sets of red, green and blue density valueswhen transferring the film to video using a telecine. By defining thewaveform monitor readings for the red, green and blue voltages whichcorrespond to the three densities, each telecine machine can be alignedto a common standard for the transfer of color negative films, whichenables the determination of scene exposure conditions directly fromtelecine transfers as described below.

The most important density value is that corresponding to the correctexposure of a standard 18% "gray card" which is commonly used bycinematographers/directors of photography in their lighting set-up. Inaccordance with a preferred embodiment of the invention, two otherdensity values which correspond to 90% reflectance and 3% reflectanceare used together with the 18% reflectance, to mirror the straight lineportion of the film characteristic within the telecine. These valuesallow maximum advantage to be taken of the latitude available withinfilm stocks for the determination of scene exposure conditions. It willbe appreciated that specular reflections and deep blacks may lie outsidethe range of reflectances described above, but these can be explored bya colorist or operator of the telecine using the full range available inthe telecine machine.

In accordance with one embodiment of the present invention, FIG. 1 showsa reference element 10 which comprises a length of film strip havingthree patches 12, 14, 16 formed thereon of known densities. The element10 is preferably a motion picture negative photographic film strip(e.g., 35 mm or 16 mm), such as Eastman EXR 200T negative film (EastmanKodak Company), which has been exposed and processed to provide patcheswith specific known density values. Patches 12, 14, 16 are preferablyarranged on the element 10 so that they fill a complete frame, that is,for 35 mm film the patches together have overall dimensions ofapproximately 22 mm by 16 mm, each patch having a width of approximately5 mm. Each patch 12, 14, 16 in accordance with a preferred embodiment asdescribed above comprises a horizontal gray scale formed by correctlyexposing a target having patches of a 3% reflectance, an 18% reflectanceand a 90% reflectance respectively with a negative working photographicfilm, and standard photographic processing (such as Kodak ECN-2processing as described in the Kodak H-24 Manual, Manual for ProcessingEastman Motion Picture Films) to form patches having predetermined,known density values. As mentioned above, the gray scale values arechosen to mirror the straight line portion of the green sensitometriccurve which is characteristic of normally exposed Eastman EXR filmstocks as shown in FIG. 2. While it is preferred to use a correctlyexposed and processed negative working photographic film as thereference element, the reference element may also be formed directly,e.g., by printing dyed or pigmented patches on a support with knowndensities corresponding to those which are obtained by correct exposureand processing of a negative film.

The Status M densities for each of the patches 12, 14, 16 in relation tored, green and blue for a reference element in accordance with apreferred embodiment formed from Eastman EXR 200T negative film areshown in Table 1.

                  TABLE 1                                                         ______________________________________                                                DENSITIES                                                             PATCH     RED          GREEN   BLUE                                           ______________________________________                                        WHITE     1.17         1.69    2.08                                           GRAY      0.83         1.28    1.64                                           BLACK     0.41         0.74    1.05                                           ______________________________________                                    

Although Table 1 gives a set of preferred values for red, green and bluedensities for each patch, it will be readily appreciated that otherdensity values may be utilized in accordance with the reflectanceschosen for a particular target from which the element is made.

Similar reference elements (not shown) can also be produced for Super 16 mm motion picture negative film stocks.

Each reference element 10 may be produced by shooting the gray scalesthereon using a set of correct exposure parameters, such as those givenin Table 2 for 200 speed film, and standard ECN-2 motion picture filmphotographic processing. Examples are given for 35 mm and 16 mm filmstock.

Table 2.

                  TABLE 2                                                         ______________________________________                                                 35 mm film stock                                                                          S16 mm film stock                                        ______________________________________                                        Camera     Aaton 35/1    Aaton XTR                                            Lens       Zeiss 135 mm  Zeiss 135 mm                                         Lens aperture                                                                            T4            T4                                                   Lights     2 × 2 K Quartz 8.7 eV                                                                 2 × 2 K Quartz 8.7 eV                                     on gray       on gray                                              Target distance                                                                          2.1 m         2.8 m                                                ______________________________________                                    

Naturally, although the reference element 10 of FIG. 1 only shows onegray scale arrangement having patches 12, 14, and 16 in accordance witha preferred embodiment, it will be readily appreciated that any numberof such arrangements can be provided on the element 10 for ease ofaccess by the telecine operator.

In order to set up a telecine in accordance with the reference element10, it is loaded into the telecine in the normal way. Using only theprimary controls of lift (detail in black areas), gain (brightness) andgamma (contrast), and the primary color correction system, the controlsare adjusted to achieve predetermined waveform monitor readings so thatthe three patches 12, 14, 16 give equal red, green and blue values atthe waveform monitor. Minor color correction adjustments may also benecessary to fine-tune the setting. The settings are then stored in thetelecine for recall at any time. The element 10 can then be removed fromthe telecine and stored in a suitable way to prevent it from fading.

The reference element of the present invention is used to calibratetelecines in a similar manner to that in which reference density patchesare used to calibrate densitometers. Predetermined waveform monitorvalues (reference video voltages) are assigned for the red, green, andblue video signals obtained from the gray scale density patchescorresponding to three known density values. The preferred red, greenand blue reference video voltages associated with the preferred threedensity patches 12, 14, and 16 corresponding to 3% Black, 18% Gray, and90% White reflectances are given in Table 3.

                  TABLE 3                                                         ______________________________________                                               PATCH VOLTAGE, V                                                       ______________________________________                                               BLACK 0.03                                                                    GRAY  0.25                                                                    WHITE 0.50                                                             ______________________________________                                    

In this way, two telecines can be set up using the element 10 andtransfer identical densities into identical red, green and blue videosignals.

Experiments to verify this were carried out using four differenttelecine machines made by Rank Cintel Limited, each machine beinglocated in a different country, that is, in Belgium, France, UnitedKingdom and the United States of America. These machines were designatedas W, X, Y and Z in accordance with Table 4.

                  TABLE 4                                                         ______________________________________                                        DESIGNATION TELECINE MACHINE                                                                              COUNTRY                                           ______________________________________                                        W           Ursa            Belgium                                           X           Mark IIIC       France                                            Y           Ursa Gold       United Kingdom                                    Z           Ursa Gold       USA                                               ______________________________________                                    

Each telecine machine was set up using an element 10 of the presentinvention, and the red, green and blue video voltages were measured fora twenty-one step sensitometric strip of Eastman EXR negative filmstocks as given below:

a) Eastman EXR 50D 5245

b) Eastman EXR 100T 5248

c) Eastman EXR 200T 5287

d) Eastman EXR 200T 5293

e) Eastman EXR 500T 5296

f) Eastman EXR 500T 5298

The red video voltages for the twenty-one steps of film stock e)measured on the four different telecine machines set up in accordancewith the present invention are shown in Table 5.

                  TABLE 5                                                         ______________________________________                                        STEP   RED DENSITY   W      X      Y    Z                                     ______________________________________                                        21     0.14          0.00   0.00   0.00 0.00                                  20     0.14          0.00   0.00   0.00 0.00                                  19     0.15          0.00   0.00   0.00 0.00                                  18     0.17          0.00   0.00   0.00 0.00                                  17     0.22          0.00   0.00   0.00 0.00                                  16     0.31          0.00   0.01   0.00 0.00                                  15     0.42          0.04   0.04   0.03 0.04                                  14     0.52          0.10   0.08   0.09 0.08                                  13     0.61          0.15   0.12   0.13 0.14                                  12     0.71          0.20   0.17   0.18 0.18                                  11     0.81          0.27   0.24   0.26 0.26                                  10     0.92          0.35   0.32   0.33 0.33                                   9     1.03          0.42   0.42   0.44 0.43                                   8     1.13          0.50   0.50   0.54 0.52                                   7     1.22          0.57   0.60   0.65 0.60                                   6     1.30          0.65   0.67        0.66                                   5     1.37          --     --     --   --                                     4     1.42          --     --     --   --                                     3     1.48          --     --     --   --                                     2     1.52          --     --     --   --                                     1     1.55          --     --     --   --                                    ______________________________________                                    

The red, green and blue video voltages of the sensitometric strips weremeasured, and a series of tables were prepared which established arelationship between video voltages and the sensitometric stripdensities (one table being derived for each telecine and each negativefilm stock). The densities were then converted into Transfer Points bydividing by 0.025 and off-setting the obtained values to arbitrarilyobtain twenty-five Transfer Points for the laboratory aim density valuescorresponding to normal exposure of an 18% gray card. This was carriedout to make Transfer Points correspond to values for Printer Lightspreviously obtained when the negative film is actually printed.

For each of the film stocks mentioned above, a table was derived foreach of the telecines. As the results for the Transfer Points were veryclose, a single table of averaged results was then obtained for eachfilm stock.

It was additionally found that averaging the results for the differentfilm stocks to provide a single final table yielded a small accuracyloss which was within acceptable limits, that is, within ±2 TransferPoints. The table of averaged Transfer Points determined this way isgiven in Table 6.

                  TABLE 6                                                         ______________________________________                                        RED             GREEN       BLUE                                              Exposure                                                                             Voltage  Transfer                                                                              Voltage                                                                             Transfer                                                                            Voltage                                                                              Transfer                           (Stop) (V)      Point   (V)   Point (V)    Point                              ______________________________________                                               0.00      3      0.05   3    0.05    3                                 -3     0.02      4      0.07   4    0.06    4                                        0.03      5      0.08   5    0.07    5                                        0.03      6      0.08   6    0.08    6                                        0.04      7      0.09   7    0.09    7                                 -2.5   0.05      8      0.10   8    0.10    8                                        0.06      9      0.11   9    0.11    9                                        0.07     10      0.12  10    0.12   10                                 -2     0.08     11      0.13  11    0.13   11                                        0.09     12      0.14  12    0.14   12                                        0.11     13      0.15  13    0.15   13                                 -1.5   0.12     14      0.17  14    0.16   14                                        0.13     15      0.18  15    0.17   15                                        0.15     16      0.19  16    0.18   16                                        0.16     17      0.20  17    0.20   17                                 -1     0.18     18      0.22  18    0.21   18                                        0.19     19      0.23  19    0.22   19                                        0.21     20      0.25  20    0.23   20                                 -0.5   0.22     21      0.26  21    0.25   21                                        0.24     22      0.27  22    0.26   22                                        0.26     23      0.29  23    0.27   23                                        0.28     24      0.31  24    0.29   24                                 N      0.29     25      0.32  25    0.30   25                                        0.31     26      0.34  26    0.32   26                                        0.33     27      0.35  27    0.33   27                                 +0.5   0.35     28      0.37  28    0.35   28                                        0.37     29      0.39  29    0.36   29                                        0.39     30      0.41  30    0.38   30                                        0.41     31      0.42  31    0.40   31                                 +1     0.43     32      0.44  32    0.42   32                                        0.45     33      0.46  33    0.44   33                                        0.47     34      0.48  34    0.45   34                                 +1.5   0.50     35      0.50  35    0.47   35                                        0.52     36      0.52  36    0.49   36                                        0.54     37      0.54  37    0.51   37                                 +2     0.57     38      0.57  38    0.53   38                                        0.59     39      0.59  39    0.56   39                                        0.62     40      0.61  40    0.58   40                                 +2.5   0.65     41      0.64  41    0.60   41                                        0.67     42      0.66  42    0.62   42                                        0.70     43      0.68  43    0.65   43                                        0.71     44      0.71  44    0.67   44                                 ______________________________________                                    

As can be seen from Table 6, the Transfer Points do not linearlycorrespond with the red, green, and blue video voltages. Accordingly,accurate scene exposure information is not readily available solely fromthe voltages. The Exposure (Stop) values presented in Table 6 correspondto the steps of the twenty-one step sensitometric strips. In accordancewith the invention, accurate scene exposure information is obtained byassigning Transfer Points to the voltages corresponding to the varyingdensities of the sensitometric strips in relation to the known exposureranges for the strip steps. While Table 6 presents averaged TransferPoints obtained for a variety of films and telecines, conversion tablesfor individual films and/or individual telecines may also be used ifdesired to provide exposure information. It is an advantage of theinvention that a single reference element may be used in combinationwith either an averaged conversion table to conveniently provideexposure information for most negative films, as well as with separate,independently derived conversion tables to provide precise exposureinformation for specific films.

For any two telecine machines which have been set up using a referenceelement in accordance with the present invention, the Transfer Pointswill be the same. This is in contrast to Printer Lights which tend to belaboratory specific.

Having determined a Transfer Points conversion table, it can be used toprovide exposure information for a scene in two ways: i) directly if an18% gray card has been shot at the beginning of a scene, or ii) toderive an "Exposure Level" table.

In case i) above, the 18% gray card must be included at the beginning ofthe scene. The negative film is loaded into the telecine and advanced tolocate the gray card for the first scene. The gray card will normally beincluded at the head of each roll or at the head of each new lightingset-up or at any suitable predetermined intervals. The settings inaccordance with the reference element 10 are recalled from memory, andwithout changing any controls, the red, green and blue video voltagescorresponding to the 18% gray card in the scene are read off. Thesevideo voltages can than be converted directly using Table 6 as a look-uptable (or a specialized look-up table for individual films and/orindividual telecines) into Transfer Points and the information fed backto the cinematographer/director of photography. In this way, thecinematographer/director of photography can assess the exposure of thefilm in much the same way as with Printer Light information. Thecolorist can then transfer the negative film as required. For example,high contrast and bright images can be transferred for ease of editing.

In accordance with a further embodiment of the invention, a system canbe provided which automatically determines the Transfer Points from thewaveform monitor as described above when a gray card is included in thescene. In accordance with one such embodiment, a look-up table or tablesderived as described above function as conversion means, which may beused in combination with conventional display means (such as an LEDdisplay) to directly convert the video voltages into Transfer Points anddisplay such Transfer Points values to the telecine operator.

If a gray card is not used at the beginning of the scene, case ii),because it has been forgotten or placed in the scene where asatisfactory reading cannot be obtained, Table 7, derived from Table 6,can be used to enable the colorist to provide exposure level informationfor the cinematographer/director of photography.

                  TABLE 7                                                         ______________________________________                                               Exposure                                                                             Green Video                                                            (Stop) Voltage (V)                                                     ______________________________________                                                      0.45                                                                   -1.5                                                                                 0.40                                                                   -1                                                                                   0.35                                                                   -0.5                                                                                 0.30                                                                   N                                                                                    0.25                                                                   +0.5                                                                                 0.20                                                                   +1                                                                                   0.15                                                                   +1.5                                                                                 0.10                                                            ______________________________________                                    

In order to use Table 7, the colorist must first color grade the sceneby eye using stored settings from the element 10 as a starting point (aspreviously described). The settings are recorded. The negative film isthen unloaded from the telecine and the reference element of the presentinvention loaded into the telecine. The settings applied to the sceneare then applied to the reference element, and the green video voltageof the 18% gray patch is measured. Table 7 is then used to determine theexposure level.

It will be appreciated that the method using Table 7, case ii), is notas accurate as the method using Table 6, case i), as there is a limitedexposure level from -1.5 to +1.5. This limitation is the result of thehigher subjectivity involved, that is, the settings being obtainedaccording to what a particular colorist likes. This means that imageswhich have been too heavily over- or under-exposed will be corrected indifferent ways by different colorists.

It is also possible to include a reference element in accordance withthe present invention on the leader attached to the negative film Thishas the advantage that there is no need to reload the element whenderiving the Printer Light information when no gray card is present inthe scene.

An additional benefit of the element of the present invention is that itcan be used to provide a starting point for grading of a scene shot onnegative film. This saves time and adds consistency to the results of atelecine transfer. The reference element of the present invention willenable a telecine machine to satisfactorily transfer the vast majorityof Eastman EXR negative film stocks. A proper tone scale reproduction isensured and the outstandingly good color to neutral balance of thesefilm stocks means that even color correction is quite small.

A further benefit of the reference element in accordance with thepresent invention is that three horizontal density patches can be usedto check for telecine shading problems. However, it will be appreciatedthat the density patches may also be vertically arranged on thephotographic element.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

What is claimed is:
 1. A method of transferring a scene recorded onphotographic negative film to video using a telecine, the methodcomprising the steps of:a) setting up the telecine so that predeterminedwaveform readings are obtained for a reference film element comprisingat least one gray scale portion comprising density patches correspondingto three known density values; b) storing the telecine set-up settings;c) loading a scene on photographic negative film into the telecinewherein the scene includes a gray card; d) using the stored telecinesettings to effect transfer of the scene to video; e) determining red,green and blue video voltages for the gray card; and f) converting thered, green and blue video voltages to Transfer Points between 0 and 50to provide exposure information for the scene by referring to a look-uptable derived from measuring the red, green, and blue video voltages forstep sensitometric strips of negative film stock on a telecine set-up inaccordance with step a), correlating the measured voltages to thesensitometric strip densities, and converting the sensitometric stripdensities into Transfer Points by dividing by 0.025 and off-setting theobtained values to obtain twenty-five Transfer Points for the laboratoryaim density values corresponding to normal exposure of an 18% gray card.2. A method according to claim 1, wherein the density patches of thereference element correspond to densities obtained in a color negativephotographic film after correctly exposing the film to a targetcomprising a black, a gray and a white region, and standard colornegative film processing.
 3. A method according to claim 2, wherein theblack region of the target is a 3% reflectance region, the gray regionis an 18% reflectance region and the white region is a 90% reflectanceregion.
 4. A method according to claim 3, wherein the predeterminedwaveform readings obtained for the reference element are 0.03 volts foreach of the red, green, and blue video signals corresponding to the 3%black reflectance region, 0.25 volts for each of the red, green and bluevideo signals corresponding to the 18% gray reflectance region, and 0.50volts for each of the red, green, and blue video signals correspondingto the 90% white reflectance region.
 5. A method according to claim 4,wherein the red, green and blue video voltages are converted to TransferPoints between 0 and 50 by referring to a look-tip table derived frommeasuring the red, green, and blue video voltages for step sensitometricstrips of negative film stock on a telecine set-up in accordance withstep a), correlating the measured voltages to the sensitometric stripdensities, and converting the sensitometric strip densities intoTransfer Points by dividing by 0.025 and off-setting the obtained valuesto obtain twenty-five Transfer Points for the laboratory aim densityvalues corresponding to normal exposure of an 18% gray card.
 6. A methodaccording to claim 3, wherein the gray scale portion fills a full frameon the element.
 7. A method according to claim 6, wherein the gray scaleportion is horizontally arranged on the element.
 8. A method accordingto claim 2, wherein the element comprises an exposed and processed colornegative photographic film.
 9. A method according to claim 3, whereinthe white density patch of the element has a red density value of about1.17, a green density value of about 1.69, and a blue density value ofabout 2.08, the gray density patch of the element has a red densityvalue of about 0.83, a green density value of about 1.28, and a bluedensity value of about 1.64, and the black density patch of the elementhas a red density value of about 0.41, a green density value of about0.74, and a blue density value of about 1.05.
 10. A method according toclaim 9, wherein the gray scale portion fills a full frame on theelement.
 11. A reference film element for use with a telecine transferdevice, said element comprising a gray scale portion, wherein the grayscale portion consists essentially of three density patches whichcorrespond to densities obtained in a color negative photographic filmafter correctly exposing the film to a target comprising a 3%reflectance black region, an 18% reflectance gray region and a 90%reflectance white region, and standard color negative film processing.12. An element according to claim 11, wherein the gray scale portionfills a full frame on the film.
 13. An element according to claim 12,wherein the gray scale portion is horizontally arranged on the element.14. An element according to claim 11, which comprises an exposed andprocessed color negative photographic film.
 15. An element according toclaim 11, wherein the white density patch of the element has a reddensity value of about 1.17, a green density value of about 1.69, and ablue density value of about 2.08, the gray density patch of the elementhas a red density value of about 0.83, a green density value of about1.28, and a blue density value of about 1.64, and the black densitypatch of the element has a red density value of about 0.41, a greendensity value of about 0.74, and a blue density value of about 1.05. 16.An element according to claim 15, wherein the gray scale portion fills afull frame on the element.
 17. An element method according to claim 16,wherein the gray scale portion is horizontally arranged on the element.18. A system for providing exposure information during the transfer of ascene which includes a gray card recorded on negative film to videousing a telecine, the system comprising:a reference film elementcomprising at least one gray scale portion comprising density patchescorresponding to three known density values, the element being used forsetting up the telecine so that predetermined waveform readings areobtained for the gray scale portion of the photographic element;conversion means for determining red, green and blue video voltages forthe gray card and for converting these voltages to Transfer Pointsbetween 0 and 50, comprising a look-up table derived from measuring thered, green and blue video voltages for step sensitometric strips ofnegative film stock on a telecine set-up with the reference element,correlating the measured voltages to the sensitometric strip densities,and converting the sensitometric strip densities into Transfer Points bydividing by 0.025 and off-setting the obtained values to obtaintwenty-five Transfer Points for the laboratory aim density valuescorresponding to normal exposure of an 18% gray card; and display meansfor displaying the Transfer Points for the scene.
 19. A system accordingto claim 18, wherein: the density patches of the reference elementcorrespond to densities obtained in a color negative photographic filmafter correctly exposing the film to a target comprising a 3%reflectance black, an 18% reflectance gray and a 90% reflectance whiteregion, and standard color negative film processing.